Directional control means for movable trucks and the like



May 28, 1940. 1. F. SCHRECK DIRECTIONAL 'CONTROL MEANS FOR MOVABLETRUCKS AND THE LIKE Filed June 6, 1939 4 Sheets-Sheet 1 i H I lailrlillllllllillfli ,IDIIIIWH INVEN fizwlll z FJZfiYJeG/H y 1940- I. F.SCHRECK 2,202,068

DIRECTIONAL CONTROL MEANS FOR MOVABLE TRUCKS AND THE LIKE Filed June 6,1939 4 Sheets-Sheet 2 Flag, 3

INVENTO P HfTOR/VEY y 28, 1940- I. F SCHRECK 2,202,068

DIRECTIONAL CONTROL MEANS FOR MOVABLE TRUCKS AND THE LIKE Filed June 6,1939 4 SheetsSheet 5 y 28, 1940- F. SCHRECK 2,202,068

DIRECTIONAL CONTROL MEANS FOR MOVABLE TRUCKS AND THE LIKE Filed June 6,1939 4 Sheets-Sheet 4 INVENTGR [WWI z 2. 15 cZ/zne. a/C

L WITNE MM Patented May 28, 1940 UNITED STATES DIRECTTONAL CONTROL MEANSFOR MOV- ABLE TRUCKS AND' THE LIKE Irvin F. Schreck, Cleveland, Ohio,assignor to Bond Foundry & Machine Company, Manheim, Pa, a corporationof Pennsylvania Application June 6, 1939, Serial No. 277,583

16 Claims.

This invention relates to movable trucks, racks, and similar vehiclesfor transporting articles over short distances such as about a shop ormill and is particularly directed to the provision, in a truck or thelike having swivel casters, of means including a supplementarynon-swiveling caster, preferably adjacent each end of the truck, tofacilitate control of the direction of its movement, especially when itis being pushed from the rear.

When all casters on a truck of this general character are free to swivelit is difficult to guide it, as the swivel casters move about theirswivel axes in directions other than parallel to the desired path oftravel of the truck, and my invention therefore contemplates bringing asupplementary caster at the leading end of the truck into engagementwith the floor to facilitate accurate control of the direction of travelof the truck by inducing the swivel casters to remain'in alignmentparallel to said desired path of travel, especially when the truck ismanipulated from its opposite end. The supplementary casters arerotatable in engagement with the floor on axes normal to thelongitudinal center line of the truck and are incapable of swiveling asthe load supporting casters do, as I have found greatly enhanced controlof the truck is attained when the load supporting casters do notparticipate in the determination of the direction of its travel but areautomatically constrained to follow the desired course by the action ofone of the supplementary casters.

Moreover, the invention in certain of its embodiments also contemplatesautomatically bringing a direction-controlling supplementary caster intocontact with the floor upon manipulation of a folding push bar at theend of the truck which when raised to operative position affords aconvenient hand grip for the operator to facilitate moving and guidingthe truck. Additionally, some embodiments of the invention include meansfor yieldingly maintaining the supplementary nonswiveling caster inengagement with the floor during movement of the truck whereby suchcaster is caused to closely follow the floor and remain in contact withit even when irregularities are encountered which might otherwise causeit to either assume an excessive proportion of the truck load or else,as when passing over a depression in the floor, clear the floor entirelyand thus become inoperative to control the swivel casters. It istherefore a principal object of the invention to provide in a truck orsimilar vehicle having swivel casters, a supplementary non-swivelingcastenpreferably one adjacent each end. of the truck, adapted to bebrought into engagement with the floor for rotation only in a planeparallel to thesides of the truck to thereby facilitate control of itsdirection of movement over the floor.

A further object is to provide automatic mech- .5 anism for moving anon-swiveling caster into yielding engagement with the floor preparatoryto manipulation of the truck to facilitate control of the direction ofmovement of the latter and for thereafter retracting said caster fromfloor en- ,g gagement to permit the truck to be moved sideWise on itsswivel casters in a direction transversely of the plane of rotation ofthe non-swiveling caster wheel.

Another object of the invention in certain of its embodiments is toprovide, in a truck having swiveling load supporting casters, asupplementary non-swiveling caster adjacent each of its ends and meansinterconnected with such supplementary casters whereby they mayselectively be brought into engagement with the door by manipulation ofoperating means adjacent the respectively opposite ends of the truck tofacilitate guiding it as it is moved along the floor.

' Other objects, purposes and advantages of the invention will hereaftermore fully appear or be understood from the following description ofcertain illustrative embodiments thereof shown in the accompanyingdrawings, and While in general its objects and. purposes are somewhatanalogous to those of the caster control means for movable trucks andthe like forming the subject of U. S. Letters Patent of Irvin F. Schreckand Chester S. Mann No. 2,132,973, issued October 11, 1938, the presentinvention constitutes improvement thereon in certain respects.

In the drawings, Fig. 1 is a fragmentary side elevation, partly invertical section, of a truck equipped with one embodiment of theinvention shown in position for operation of the truck from the lefthand end in said figure;

Fig. 2 is a' bottom plan View thereof and- Fig'. 3 is an enlarged endview of the truck with the control mechanism in neutral or inoperativeposition, other positions of certain parts being indicated by brokenlines. 1

Fig. 4 is a fragmentary view generally corresponding to a portion ofFig. 3 but showing a modified embodiment of the invention adapted forfoot operation;

Fig. 5 is a fragmentary top plan view of the mechanism shown in Fig. 4;

. Fig. 6 is a fragmentary detail corresponding to Fig. 4 but showingmore clearly certain parts in positions which are indicated therein onlyin broken lines and Fig. 7 is a fragmentary staggered vertical sectionon the line '|'I in Fig. 4.

Fig. 8 is a fragmentary end view corresponding generally to Fig. 3 butshowing another modification of the invention adapted for footoperation;

Fig. 9 is an enlarged fragmentary top plan view thereof and Fig. 10 is afragmentary side elevation of the control mechanism with a portion ofthe truck body in vertical section.

Fig. 11 is a fragmentary side elevation, also enlarged, of a truckequipped with another embodiment of the invention;

Fig. 12 is a fragmentary top plan view of mechanism shown in Fig. 11removed from the truck and Fig. 13 is an end View thereof partly invertical section;

Figs. 14 and 15 are respectively a fragmentary side elevation andfragmentary bottom plan View generally corresponding to Figs. 1 and 2but on a smaller scale showing still another embodiment of theinvention.

In the several figures like reference numerals are used to designate thesame parts, those performing the same or substantially similar functionsin the several embodiments of the invention illustrated beingdistinguished by alphabetical exponents appended to their respectivedesignating numerals. 7

Referring first more or less generally to the drawings the truck T, thespecific details of construction of which are not material, is merelytypical of any truck or other vehicle adapted to be supported fromswivel casters and may be provided with two pairs of such casters C, Crespectively located adjacent its ends. In accordance with the inventionsupplementary casters generally designated I I are disposed at oppositeends of the truck T substantially on its center line and generallyU-shaped push bars 2, 2' are hinged to brackets 3, 3, l, 4 on the endsof the truck body whereby either bar when raised affords a hand grip tofacilitate operation of the truck. In some embodiments of the inventionshown in the drawings chains 5, 5 interconnect the push barsrespectively with the subjacent supplementary casters and the latter areinterconnected by a rod Il' whereby they are simultaneously operated tofacilitate the guiding and control of the truck when either push bar israised preparatory to moving it.

As the supplementary casters I, i at the opposite ends of the truck aresubstantially identical in structure and operation in each embodiment ofthe invention, specific description of one of them in each case will beunderstood as applying also to the other at the opposite end.

Thus the caster Ia at the right hand end of the truck shown in Figs. 1,2 and 3, which assists the guiding and control of the truck Ta .when itis being operated through the instrumentality of the push bar 2a at itsleft hand end in said figures comprises a base plate 6a secured to thetruck bottom through the cooperation of an integral upstanding flange Iafitting over the adjacent edge of a corner iron t forming a part of thetruck frame and a clamp 8 held to the base plate by bolts 9 and nuts Illand embracing the horizontal flange of the corner iron. Thesupplementary casters thus may readily be attached to conventionaltrucks whether initially constructed for their reception or not.

The plate 6a includes an integral downwardly depending ear Masubstantially aligned vertically with the flange Ia and another ear I50parallel thereto adjacent the opposite edge of the base plate. Theseears are provided with aligned holes IBa each having at its lower partflat faces intersecting at an inverted angle forming a notch the sidesof which are tangent to the upper circular part of the hole, as bestshown in Fig. 3. A rod Ila extends through these holes in the base plateears of both casters and interconnects the latter beneath the truck.Between the base plate ears the rod Ila carries a sleeve I8a secured tothe rod by a set screw Ma, and an integral downwardly and laterallyprojecting arm 20a on the sleeve supports an axle 2Ia which extendslaterally outwardly for the reception of the supplementary caster wheel22a rotatable on the axle but restrained by the rigid attachment of theaxle to the arm from swiveling about a vertical axis as do the castersC.

The arm 20a is formed with an integral projection 23a and the chain 5asuspended from the push bar 2a is attached to this arm by a cap screw24a, the chain thus interconnecting the caster and push bar in such away that when the latter is raised an upward pull is exerted upon theadjacent supplementary caster arm 2 Ia causing the latter to turn therod Ila generally about its axis; due to the loose fit of the rod in theholes Ifia the first movement of the arm, however, causes the rod toride out of the notches in these holes and move upwardly into theircircular parts,

Thus as either push bar is raised preparatory to its use as a handle forguiding and moving the truck the adjacent chain automatically actuatesthe supplementary guiding caster mechanism without attention from theoperator to facilitate the guiding and control of the truck as will nowbe more fully described.

For example, when the mechanism is in neutral position as indicated infull lines in Fig. 3 and the push bars at both ends of the truck arelowered as when the truck is merely standing unattended, the casters Iaand Hz and their associated mechanisms are substantially in staticbalance and their interconnecting rod I'Ia rests in the notches at thebottoms of the holes I6a with its lower faces forming angles ofsubstantially 45 with the vertical and horizontal. In this position thearms 20a, 20a hold both supplementary caster wheels elevated above thefloor and above the plane of the swivel casters C, C, and the truck maybe pushed in any direction without the aid of the supplementary castersso long as the push bars remain lowered.

When the truck is to be pushed for an appreciable distance, however, itis usually most convenient to utilize one of the push bars and raisingeither of them for this purpose brings into play the supplementarycasters to facilitate guiding and control of the direction of travel.Thus when the push bar 2a is raised to operative position as shown inFigs. 1 and 2 it acts through the chain 5a to raise the subjacentsupplementary caster Ia and bring the rod Il'a out of the notches in theholes I6a to rotate it about its longitudinal axis in a counterclockwisedirection as viewed in Fig. 3. The caster Ia under these conditionsmoves to its upper dotted line position indicated in said figure whilethe supplementary caster Ia at the opposite end of the rod and adjacentthe now leading end of the truck, being disposed on the opposite side ofthe rod from 75 the caster la, is brought by the movement of the rodinto engagement with the floor, as indicated by its lower dotted lineposition in Fig. 3. Both operating chains 5a, 5a are desirably soadjusted that the adjacent supplementary caster is moved through asomewhat wider arc than one just sufiicient to bring the supplementarycaster at the opposite end of the truck into contact with the floor whenthe push bar is lifted to operative position, and the rod Ha istherefore placed under torsional tension so that its inherent torsionalelasticity yieldingly maintains such supplementary caster in intimateengagement with the floor as long as the push bar remains elevated. Thusthroughout the time the latter is being utilized in the normal way foroperating the truck the supplementary caster is caused to closely andyieldingly follow any irregularities in the floor rather than ride overdepressions without touching them or partially lift the truck uponencountering an obstruction. The torsional yieldability of the rodmoreover absorbs vibration and slight movements of the caster andprevents their transmission to the hands of the operator, and/oroscillation of the push bar on its hinges during operation of the truck,while the firmness with which the caster is maintained in contact withthe floor, combined with its inability to rotate in any plane other thanone parallel to the center line of the truck, tends to restrain thetruck against movement other than in a plane parallel with such centerline except when positively directed in a difierent path by theoperator. The usual difficulties in directing swivel caster trucks,which have arisen from absence of adequate control of the planes inwhich the caster wheels rotate are thereby eliminated and the ease andconvenience with which the truck can be guided in a desired directiongreatly enhanced.

The push bar, when released, again folds against the truck end and theconsequent relaxation of the tension on the adjacent chain enables therod Ila to return to its notches in the holes l6a and thereby restorethe supplementary casters to balanced position with both wheels elevatedabove, and therefore out of engagement with, the floor. The notches,moreover, tend to restrain the rod from turning about its axis and keepboth wheels retracted from the floor even when the truck is moved over arough surface as an ordinary swivel caster truck so that it may bepushed sidewise, or in any other direction, without the aid of the pushbars, and the supplementary casters then do not participate in orinterfere with the direction of movement of the swivel casters C, C inany way.

In the embodiment of the invention shown in Figs. 4-7 inclusive thesupplementary casters lb, 1'!) and certain associated parts aresubstantially the same as in that just described but somewhat differentmechanism is utilized for operating them. The supplementary casters lb,l'b in these figures are operated by chains at 5b, 5'?) at the ends ofthe truck but these chains, instead of being connected with push barsfor automatic action upon manipulation of such bars, are connected withmechanism arranged for foot operation independently of any push bar orother guiding means with which the truck may be equipped. Thesupplementary caster at either end of the truck is thus brought intoplay by operation of foot actuated mechanism disposed at its oppositeend and may be released in a like manner when, for example, the truck isto be pushed sidewise.

The mechanism controlling the operation of the supplementary casters lb,l'b is supported from an integral specially formed part of the casterbase plate 6b which is thus provided with an overhanging web 30bdefining with the end of the base plate an inverted channel 3| b withinvwhich the foot actuated levers are arranged for pivotal movement in avertical plane parallel to the adjacent end of the truck. A mainactuating lever 32b is thus pivotally supported on a pin 33b extendingacross the channel and threaded into the base plate and is provided withan outwardly projecting foot pedal 34b by whichit is operated. On itsopposite end this lever has an integral projection 35b adapted toreceive a cap screw 35b whereby the chain 5b is attached to the lever,the opposite end of this chain being connected to the projection 23'b onthe arm 20'?) of the adjacent supplementary caster lb.

Thus when the foot pedal 34b is depressedthe chain is raised, operatingthe supplementary casters lb, Ib and associated mechanism in the sameway that the casters la, la are operated by raising of the push bars inFigs. 1-3 inclusive. Means are also provided for releasably locking thismechanism in operative position to eliminate the necessity for attentionof the operator during movement of the truck, such means comprising alatch lever 37b pivoted on a pin 38b spanning the channel 3Ib andthreaded into the base plate. The end of this lever nearest the mainlever is adapted to fall by gravity into a notch ltlb formed in theupper edge of the latter when the notch moves into position to receiveit upon movement of the main lever to operate the supplementary castersand the latch lever thus automatically holds the main lever looked afterthe foot is removed from the pedal 33b; the supplementary caster lb atthe opposite end of the truck is consequently held in engagement withthe floor to assist in guiding the truck until the latch lever issubsequently operated to release the main lever, the latch lever havingfor this purpose a foot actuated operating pedal Mb projectingoppositely with respect to its pivot from the main lever and operable torelease the latter to permit the supplementary casters to return toneutral position.

Thus with regard to the guiding and controlling iunction of thesupplementary casters this embodiment of the invention operatessimilarly to the one first described, the independently operable leversprovided for bringing them into play being preferred in some instances,as in trucks not equipped with push bars or comparable guiding handles,or when it is not desired to have the supplementary casters operateautomatically. It will of course be understood that the latch lever 37?)rests against the main lever 32b Without engaging in the notch Mb bothwhen the mechanism is in neutral position and when the main lever 32'!)and associated actuating mechanism at the opposite end of the truck hasbeen operated to bring the supplementary caster lb into engagement withthe floor, and that when the entire mechanism is in neutral orinoperative ment of the invention shown in Figs. 1-3.

Of course, after being so actuated, either main lever may readily bereleased by moving the adjacent latch lever by foot pressure on itspedal to withdraw its end from the notch in the main lever and allow therod ilb to return to its notches in the holes I61: and hold the castersin neutral position.

Figs. 8-10 inclusive illustrate other mechanism for actuatingsupplementary casters lc, lc corresponding to those shown in theprevious figures, its operation being somewhat similar to that of themechanism shown in Figs. 4-7. Instead of including means for lifting onesupplementary caster to turn the caster connecting rod and bring thesupplementary caster at the opposite end of the truck into engagementwith the floor, however, in this embodiment of the invention means areprovided for directly actuating the rod ilc which is therefore extendedan appreciable distance beyond the ends of the truck to facilitate theirconnection therewith. Thus a main actuating lever 320 has a square holewhich receives the adjacent end of the rod and is secured to it by a setscrew 42c whereby the shaft may be turned (clockwise in Fig. 8) by footpressure on an integral pedal 3 30 formed on this lever to operate theshaft in substantially the same manner as the corresponding rod in thepreceding figures is operated by raising one supplementary caster tobring the supplementary caster [0 at the opposite end of the truck intoyielding engagement with the floor. Means are also here provided forreleasably locking the main lever in operative position comprising afoot actuated latch lever 3'lc pivoted to the main lever 320 on a pin380. The latch lever extends through a slot in the main lever 32c andhas an integral pedal Me projecting laterally above the upper surface ofthe main lever oppositely from the pedal 34c thereon. The downwardlyprojecting lower end of the latch lever beneath the main lever is curvedinwardly toward the truck and forms a detent 43c adapted to engageratchet teeth 440 on the lower edge of the ear l tc of the adjacentsupplementary caster base plate, the latch lever being urged about itspivot 380 in a direction to maintain this detent in engagement with theteeth by a spring 450 interposed between the pedal 4 I0 and an abutmentlfic integral with and projecting adjacent this pedal from the mainlever 320. Thus when the latter is depressed to operate the rod lie thedetent engages in a tooth 44c and automatically holds the main leverdepressed until released by disengagement of the detent from the ratchetteeth upon foot operation of the latch lever by its pedal 4 l c.

The embodiment of the invention shown in Figs. 11-13 inclusive comprisessupplementary casters Id, I'd which are of different construction fromthose heretofore described, and while adapted to be operated by pushbars similar to those in Figs. 1-3 or other suitable mechanism, theoperating mechanism employed is largely a matter of choice and chains5d, 5d in the drawings therefore merely illustrate the manner in whichconnection of such operating mechanism with the casters may be effected.

The supplementary casters ld, l'cl comprise caster wheels 2201, 22dadapted for vertical movement relatively to the truck as distinguishedfrom the generally arcuate movement of the supplementary caster wheelsheretofore described and the wheels 22d, 22d may therefore be providedwith fiat treads instead of the curved treads utilized on the latter tofacilitate positive engagement with the floor during oscillation causedby irregularities therein. In this embodiment of the invention thecaster wheels 22d, 22d are moved vertically by cam action and arebrought into positive engagement with the floor and retained thereinthrough manipulation of their operating means in such a way as toinhibit their yielding movement upon encountering irregularities in thefloor.

The supplementary caster ld thus includes a base plate 6d secured to thebottom of the truck and having a pair of integral downwardly dependingarms 4703 which support a transverse shaft 48d to which an eccentric cam39d rotatable with the shaft is secured by a set screw 50d forcontrolling the position of the caster wheel. The shaft 38d is operatedby a crank arm 5ld secured to one of its ends and a collar 52d at itsother end cooperates with the crank arm to retain the shaft in properposition longitudinally while an operating chain 5d and rod lldinterconnecting the casters ld, I'd are fastened to the projecting endof the crank arm by a nut ingly resist its downward movement under theinfluence of the cam 49d which operates to depress the blooks through anactuating yoke 59d formed by slidable plungers 60d extending throughholes in the base plate arms and an interconnecting rigid cross bar 86dengaged by the cam face. Thus when the cam 39d is moved by operation ofthe crank arm d clockwise to the position shown in Fig, 11 the casterwheel 22d is depressed against the force of the springs 58d into floorengaging position, and when the cam moves or is free to move in theopposite direction the springs raise the wheel from the floor.

The movements of the cams 49d and 49d of both casters are controlledsimultaneously through interconnection of their crank arms 51d, 5! 'd bythe rigid rod lid, and connections of the latter with the chains 5'61,5d respectively at the ends of the truck therefore operate both casterswhen either chain is pulled, as by raising a superjacent push bar (notshown) from. which the chain passes to connection with the casters overa sheave (62d or 62d) at a lower corner of the truck. Thus the cam ofthe supplementary caster at the end of the truck opposite that at whichthe push bar or the like being operated is posi tioned is rotated todepress the corresponding caster wheel while the wheel of the othercaster simultaneously rises above its neutral position under theinfluence of its springs. The cams and crank arms are desirably soadjusted and arranged that neither cam. ever attains full deadcenterposition and the force of the springs of the depressed caster thereforeis sufficient to return the entire supplementary caster mechanism toneutral position when the chain is released, its return to this positionbeing enhanced somewhat by the weight of the rod llcZ inducing thesprings 58d of both casters to become mutually balanced.

The embodiment of the invention shown in Figs. 13 and 14 is adapted forthe same purposes as the others and due to its greater simplicity andrelatively inexpensive construction it may sometimes be preferred.

It comprises a longitudinally extending bifurcated rod I'le pivoted atits center on a bracket 646 depending from the bottom of the trucksubstantially at the intersection of its longitudinal and transversecenter lines. The rod extends slightly beyond the ends of the truck andis connected at its ends through chains-5e, 5'e respectively with pushbars 2e, 2'e. Near its ends the rod supports transversely disposed axles2|, 2le on which supplementary caster wheels 22c, 22'e can rotate in aplane parallel to the longitudinal center line of the truck and bebrought into engagement with the floor by appropriate movement of therod on its pivot induced by operation of the push bars 2e, Ze, throughthe chains 5e, 5e, to assist in guiding the truck in the same manner asthose in the embodiments of the invention already described. As theirstructure and operation will be apparent from the foregoing morespecific reference thereto would be superfluous.

While I have herein illustrated and described with considerableparticularity several embodiments of my invention operating inaccordance with the same general principles and adapted to facilitateguiding and control of a truck equipped with swivel casters, it will beapparent that they embody many differences in details of constructionand specific features of their operation and that numerous otherembodiments thereof op erating according to these general principles maybe devised; it is therefore to be understood that I do not desire orintend to restrict or confine my invention in any way to any or all ofthe embodiments to which reference hasherein been made or to anyspecific details of the construc-' tion of any embodiment thereof aschanges and I modifications in the form, structure, and arrangement ofthe several parts, in the operating mechanisms utilized therefor, and inthe mode of operation employed will readily occur to those skilled inthe art and may be made if desired without departing from the spirit andscope 'of the invention as defined in the appended claims.

Having thus described my invention, I claim and desire to protect byLetters Patent of the United States:

1. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, supplementary casters respectively adjacent the endsof the truck, and means operable from the ends of the truck forselectively bringing the wheel of one supplementary caster substantiallyinto said horizontal plane while maintaining the other supplementarycaster retracted from said plane.

2. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, supplementary, non-swiveling casters adjacent the endsof the truck having wheels movable relatively thereto, and meansadjacent each end of the truck operable to bring the wheel of thesupplementary caster adjacent the opposite end thereof substantiallyinto said plane While maintaining the other supplementary caster wheelretracted therefrom.

3. In combination with a truck or the like in cluding a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane; supplementary non-swiveling casters having movablewheels adjacent the ends of the truck, means adjacent each end of thetruck operable to move the wheel of the adjacent supplementary casterrelatively to said plane, and means interconnecting the supplementarycasters operable on movement of one supplementary caster wheel in onedirection relatively to said plane to move the other such wheel in theopposite direction.

4. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, supplementary non-swiveling casters having movablewheels adjacent the ends of the truck, a rod extending longitudinallybeneath the truck interconnecting the supplementary casters, and meansadjacent the ends of the truck respectively operable to move the rod inopposite directions to thereby move a .corresponding supplementarycaster wheel substan tially into said plane.

5. In combination with a truck or the like including a plurality ofswivel castershaving caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, meansinterconnecting the supplementary casters operable when the wheel of oneis moved relatively to said plane to move the wheel of the other in theopposite direction relatively thereto, and means interconnected witheach supplementary caster for moving its wheel relatively to said plane.

6. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, a movablerod interconnecting said casters, and actuating means adjacent each endof the truck for moving the wheel of the adjacent supplementary casterin one direction relatively to said plane to thereby operate said rod tomove the wheel of the other supplementary caster in the oppositedirection relatively to said plane.

'7. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, a

rod extending between the supplementary casters supporting them formovement substantially about its axis, and means adjacent each end ofthe truck respectively operable to rotate the rod to thereby move thesupplementary caster adjacent the opposite end of the trucksubstantially into said plane.

8. In combination with a truck or the like including a plurality ofswivel casters having caster wheelsdisposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, a rod,interconnecting the supplementary casters, means carried by the rodsupporting the su plementary caster wheels for movement substantiallyabout the rod axis, means adjacent each end of the truck operable tomove the wheel of the adjacent supplementary caster about said axis inone direction relatively to said plane to thereby rotate the rod to movethe wheel of the other supplementary caster in substantially theopposite direction relatively to said plane.

9. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, a rodinterconnecting the supplementary casters, means carried by the rodsupporting the supplementary caster wheels for movement sub stantiallyabout the rod axis, and actuating means for each supplementary casteroperable to move the wheel thereof away from said plane to therebyrotate the rod and move the wheel of the other supplementary casteryieldingly into said plane.

10. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, a rodinterconnecting the supplementary casters, means carried by the rodsupporting the supplementary caster Wheels for movement substantiallyabout the rod axis, a push bar pivoted to each end of the truck, andmeans interconnecting each push bar with the subjacent supplementarycaster wheel supporting means operable on movement of the push bar inone direction to move the wheel of said supplementary caster in acorresponding direction relatively to said plane to thereby rotate therod about its axis to move the wheel of the other supplementary casterin the opposite direction relatively to said plane.

11. In combination with a truck or the like including a pliu'ality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, a rodinterconnecting the supplementary casters, means carried by the rodsupporting the supplementary caster wheels for movement substan tiallyabout the rod axis, a push bar pivoted to each end of the truck, andmeans interconnecting each push bar with the rod operable when the pushbar is moved to operative position torotate the rod and thereby move thewheel of the supplementary caster adjacent the opposite end of the truckyieldingly into said plane.

12. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, a movablerod extending longitudinally of the truck interconnecting thesupplementary casters, and means carried by each supplementary casteroperable to rotate the rod to thereby move the wheel of the other casteryieldingly into said plane.

13. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster Wheel movable into and out of said plane, anactuating lever associated with each supplementary caster, meansinterconnecting each lever with the adjacent supplementary caster wheelfor moving it in one direction relatively to said plane, and meansinterconnecting the supplementary caster wheels operable when one ismoved in said direction to move the other in the opposite directionrelatively to said plane.

14. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, anactuating lever associated with each supplementary caster, meansinterconnecting each lever with the adjacent supplementary caster wheelfor moving it in one direction relatively to said plane, meansinterconnecting the supplementary caster wheels operable when one ismoved in said direction to move the other in the opposite directionrelatively to said plane, and means for releasably locking each leverafter its actuation to move said adjacent supplementary caster wheel.

15. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movable into and out of said plane, anactuating lever associated with each supplementary caster, meansinterconnecting each lever with the adjacent supplementary caster wheelfor moving it in one direction relatively to said plane, meansinterconnecting the supplementary caster wheels operable when one ismoved in said direction to move the other in the opposite directionrelatively to said plane, and means for releasably locking each leverafter its actuation to move said adjacent supplementary caster wheel,each of said last mentioned means comprising a latching lever adapted toengage in a notch in the adjacent actuating lever to thereby inhibitmovement thereof in one direction.

16. In combination with a truck or the like including a plurality ofswivel casters having caster wheels disposed in substantially the samehorizontal plane, a supplementary caster adjacent each end of the truckcomprising a caster wheel movably into and out of said plane, anactuating lever associated with each supplementary caster, meansinterconnecting each lever with the adjacent supplementary caster wheelfor moving it in one direction relatively to said plane, meansinterconnecting the supplementary caster wheels operable when one ismoved in said direction to yieldingly move the other in the oppositedirection relatively to said plane, and means for releasably lockingeach lever after its actuation to move said adjacent supplementarycaster Wheel.

IRVIN F. SCI-IRECK.

